Actuators, which are also referred to as “converters,” “drive elements,” and “adjusting devices,” are known from the prior art. In particular, actuators are also known which convert electrical signals for at least one electromagnet into mechanical movement of an armature connected thereto. The armature, in turn, transmits at least part of the mechanical movement to a plunger, push rod or armature rod. The plunger (or push rod or armature rod) transmits at least part of the mechanical movement to at least one thrust pin, also referred to as a drive pin. The thrust pin transmits at least part of the mechanical movement to machine parts, for example to sliding cam (pieces) of a sliding cam system, which are adjusted or shifted by the aforementioned movements.
German patent applications DE 10 2008 020 892 A1 and DE 10 2011 078 525 A1 disclose actuators of the type mentioned at the outset.
The actuator in DE 10 2008 020 892 A1 includes a holding and releasing device, which fixes the thrust pin (actuator pin) in a holding position on support surfaces against the force of a pressure spring acting upon the thrust pin in the extension direction, not via magnetic forces of attraction but with the aid of a clamping effect as a result of friction-induced self-locking of a locking body. The holding and releasing device includes a stop valve, which is displaceable in the traversing direction of the thrust pin and independently thereof, as well as a flexible tongue, which applies force to the stop valve in the extension direction of the thrust pin. The flexible tongue applies force to an armature, which is fixedly connected to the stop valve, in the extension direction of the thrust pin. The actuator is used to adjust sliding cams. The disadvantage of the actuator is that the stop valve and the flexible tongue are delicate and high-precision components, which makes it expensive to mount the actuator and to manufacture its individual parts.
In the bistable actuator in DE 10 2011 078 525 A1, a pressure spring is supported on a latching device. A supporting spring which is oriented counter to the pressure spring and which is supported on a guiding sleeve for the thrust pin, or on a component connected thereto, engages with the thrust pin (actuator pin). Together with the latching device, the pressure and supporting springs form a bistable arrangement of the thrust pin. Due to this design, it is achieved that the extension of the thrust pin is initially induced by the electromagnet until a tilting point of the bistable arrangement of the thrust pin is reached and the latching device is released, so that the pressure spring then takes over the complete extension of the thrust pin into a sliding groove. A rocker is pivotable to two sides and supported centrally on an armature rod, which does not belong to the magnet housing. The rocker is operatively connected to the armature rod in such a way that the axial movement of the armature rod is transmittable to the thrust pin. The disadvantage of the actuator is that the additional supporting spring, the latching device and the rocker also represent a delicate and high-precision arrangement, which also makes it expensive to assemble and mount the actuator and to manufacture its individual parts.